Cooling Device for Engine Oil and/or Transmission Oil, Particularly in an Internal Combustion Engine

ABSTRACT

A cooling device for engine oil and/or transmission oil, particularly in an internal combustion engine, with an oil cooler which is arranged in an oil pan and through which a coolant flows. The oil cooler is formed by a plate heat exchanger ( 3 ) with coolant-carrying and oil-carrying plate intermediate spaces ( 5, 6 ). At least some of the oil-carrying plate intermediate spaces ( 6 ) open into the oil pan ( 2 ) in such a way the oil flows out of the oil pan directly via the opening ( 24 ) into the oil-carrying plate intermediate spaces ( 6 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to a cooling device for engine oil and/or transmission oil, particularly a cooling device for engine oil and/or transmission oil arranged in the oil pan of in an internal combustion engine.

2. Description of the Related Art

It is commonly known that a cooling device for engine oil and/or transmission oil of the type mentioned above is fitted to an engine housing or transmission housing. In so doing, both the coolant and the medium to be cooled must be conveyed to and from the cooling device. A cooler of this kind occupies a relatively large installation space.

Further, it is already known from DE 10 2004 036 286 A1 to provide an oil cooling device for an engine in which an oil cooler is arranged inside an oil pan at a distance from a bottom surface. Further, an oil suction opening is arranged below the oil cooler and at a distance therefrom. A construction of this kind is intended to improve the circulation efficiency of the oil in the oil pan which, in turn, should have a positive effect on the efficiency of the oil cooling itself.

EP 1 600 611 B1 discloses a construction of an oil pan for an engine and/or a transmission having an opening on the bottom which is closed by a cover. This cover has a heat exchanger for the oil comprising a coolant inlet, a coolant outlet and coolant channels fluidically disposed therebetween.

Further, an internal combustion engine with an oil pan in which oil channels are formed in the housing of the oil pan is known from DE 196 19 977 A1. The cooling device which is formed by a plate heat exchanger is arranged outside the oil pan in this case.

Further, DD 39 500 discloses a cooling device for an oil pan in which a cooling duct is guided helically from an outer inflow opening to a suction space of the oil pump which is situated approximately in the center of the oil pan. Oil which is regulated by means of a pressure relief valve is guided from the pressure line of the oil pump through a preferably nozzle-shaped opening below the level of the oil approximately horizontally into the oil layer via the oil duct.

Another oil cooling arrangement is also known from DD 85 686 in which the cooling circuit of the engine is connected to the bottom cover of the engine and is fastened to the oil pan, a strainer of the oil pump being arranged in the bottom of the oil pan which is separated from the bottom cover by a partition wall. Further, the through-channels in the cover for the flow of cooling liquid and the through-channels in the bottom for the flow of lubricating oil are formed by the ribs.

SUMMARY OF THE INVENTION

In contrast to the above, it is an object of the present invention to provide a cooling device for engine oil and/or transmission oil, particularly in an internal combustion engine, by means of which the oil can be cooled in a simple manner with respect to components and with high efficiency.

Accordingly, the cooling device has an oil cooler which is arranged in an oil pan and through which a coolant flows. According to the present invention, the oil cooler is formed by a plate heat exchanger with coolant-carrying and oil-carrying plate intermediate spaces, wherein at least some, preferably all, of the oil-carrying plate intermediate spaces open into the oil pan with a defined opening in such a way that the oil flows out of the oil pan directly via the respective opening into the oil-carrying plate intermediate spaces.

A plate heat exchanger or plate heat transfer unit of this kind makes for a simple design of the cooling device overall, wherein the cooling of the oil can be carried out in an effective and efficient manner. In particular, the fact that it is possible for the oil to flow into the heat exchanger directly via the respective oil-carrying plate intermediate spaces makes for a highly efficient cooling of the oil in connection with the relatively long flow paths in a plate heat exchanger.

Another special advantage of this construction consists in that a relatively large cooling surface can be made available by integrating the plate heat exchanger in the oil pan, which is generally not the case because of the limited installation space in externally arranged heat exchangers or coolers.

In a particularly preferable specific embodiment, the plate heat exchanger is formed by a plate assembly comprising a plurality of plates whose oil-carrying plate intermediate spaces open into the oil pan with a radial outer and/or radial inner opening with respect to the plate assembly. Accordingly, the oil can be sucked into the oil-carrying plate intermediate spaces radially in a very simple manner by means of the applied suction pressure and can flow through these oil-carrying plate intermediate spaces efficiently while transferring heat to the coolant.

Particularly favorable flow conditions are achieved due to the radial flow of oil into the oil-carrying plate intermediate spaces and the subsequent preferred radial flow through the respective plate intermediate spaces. As a result, swirling and turbulence, for example, are reduced, which has a particularly advantageous effect on the efficiency of heat transfer in the plate heat exchanger.

According to a particularly preferable specific embodiment, the oil-carrying plate intermediate spaces open into the oil pan with a radial outer opening, and the plate heat exchanger has an inner oil line connection area for an oil line which is fluidically connected in an inner heat exchanger area to the oil-carrying plate intermediate spaces, or at least to a portion thereof, in such a way that the hot oil can flow from the oil pan radially into the oil-carrying plate intermediate spaces via the radial outer openings. Subsequently, the oil flows through these plate intermediate spaces preferably radially while giving off heat so that cooled oil can finally flow out via the oil line. In a particularly preferred embodiment, at least one filter element and/or screen element is provided in the area of the respective openings through which the oil flows into the oil-carrying plate intermediate spaces. According to a particularly preferred specific embodiment, this filter element and/or screen element encloses the entire plate assembly in the radial outer circumferential area annularly and in a positive-locking manner. A cylindrical filter element and/or screen element of this kind can be fitted to the circumferential area and anchored thereon in a simple manner, for example, by positive-locking and/or friction-locking locking means and/or connection means. A filter element and/or screen element of this kind ensures in a simple manner that any contaminants such as, e.g., metal parts or the like, are retained and remain in the oil pan.

According to another particularly preferable specific embodiment, the oil line opens into the plate heat exchanger in an approximately central, medial area resulting in a substantially symmetric construction of the plate assembly. The oil line itself is preferably formed by a suction pipe line on the oil pump side so that the suction pressure can be applied to the oil in the oil pan via this suction pipe line in order to suck the oil into the plate heat exchanger via the oil-carrying plate intermediate spaces, and the openings thereof, which open into the oil pan.

It has been described at length above in connection with the preferred specific embodiment that the oil flows into, or is sucked into, the plate heat exchanger through radial outer openings. However, it is also possible in principle for the oil to be sucked into the oil-carrying plate intermediate space allowing the oil to flow radially into the oil-carrying plate intermediate spaces through radial inner openings which are formed, for example, by a medial, central recess on the heat exchanger side. In this case, the at least one oil line which carries the oil away from the oil-carrying plate intermediate spaces would have to be provided at a suitable location at the plate heat exchanger, for example, at the radial outer edge area of the plate heat exchanger. Also, a filter element or screen element would then have to be provided in the radial inner openings of the plate heat exchanger similar to the embodiment described above. This embodiment is specifically a construction that is equivalent to the embodiment with inflow on the radial outer side which was described in detail above.

A construction and arrangement of the cooling device in which the plate heat exchanger is arranged and/or suspended at a defined distance from at least a portion of the bottom walls and/or side walls in the oil pan which surround the plate heat exchanger is particularly preferred. In this way, the most favorable heat exchanger efficiencies for each application can be achieved. In a particularly preferred manner, the plate heat exchanger is fastened to supports on the housing wall side and/or connection points on the housing wall side and/or directly to the housing wall by means of finger-shaped and/or flange-shaped heat exchanger bearing elements. In particular, detachable fastening means are provided as fastening means, for example, screws which are preferably arranged so as to be easily accessible through an opening in the oil pan for assembly.

According to a construction which is particularly preferable for this purpose, the plate heat exchanger is supported and/or braced by its heat exchanger bearing elements between two or more housing walls of the oil pan, particularly between two opposite housing walls of the oil pan, in such a way that the plate heat exchanger forms a kind of tensioning element, for example. In this way, the side walls of the oil pan are supported relative to one another, which substantially reduces vibration of the side walls and therefore results in reduced noise.

For a particularly high level of functional integration the coolant channels are integrated in the heat exchanger bearing elements. These coolant channels are fluidically connected to at least a portion of the coolant-carrying plate intermediate spaces. According to another particularly preferred embodiment of the present invention, the coolant channels which are fluidically connected to the coolant-carrying plate intermediate spaces are formed by coolant channels which are integrated at least partially in a housing wall of the oil pan. A construction in which the two embodiment forms described above are combined, namely in such a way that the coolant channels integrated in the heat exchanger bearing elements are fluidically connected to the coolant channels integrated in the housing wall, is particularly preferred. The coolant channels are preferably formed by a plurality of bore holes which communicate with one another and which are simple and inexpensive to produce.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail in the following with reference to drawings, in which

FIG. 1 is a schematic view of a cross section through an oil pan with a cooling device according to the present invention;

FIG. 2 is a schematic sectional view along line A-A of FIG. 1; and

FIG. 3 is a schematic view of a cross section through an alternative embodiment of the cooling device according to the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

FIGS. 1 and 2 show different schematic cross-sectional views through a first embodiment of a cooling device 1 according to the present invention. This cooling device 1 comprises a plate heat exchanger 3 as oil cooler which is received and arranged in an oil pan 2.

As can be seen particularly from FIG. 2, the plate heat exchanger 3 is formed specifically by a plate assembly comprising a plurality of flat plates 4 which form coolant-carrying plate intermediate spaces 5 on the one hand and oil-carrying plate intermediate spaces 6 on the other hand.

The plate heat exchanger 3 is supported at supports 9, 10 on the oil pan side by means of bearing elements 7, 8 on the heat exchanger side and is secured, e.g., by screw connections 11, in such a way that the plate heat exchanger 3 is at a distance from the side walls 12 as well as from the bottom wall 13 in which an oil drain screw 14 is arranged in a customary manner.

Coolant channels 15 a, 15 b which are produced by simple bore holes are integrated in the bearing elements 7, 8 on the heat exchanger side and communicate in turn with coolant channels 16 a, 16 b which are integrated in the housing wall of the oil pan 2 and which are likewise produced by simple bore holes. In order to seal the portions of the coolant channel extending horizontally with respect to the drawing plane in FIG. 2 and opening into the outer wall, sealing plugs or closure screws 17 are arranged in these coolant channel portions. This applies also to the coolant channel 15 a in the left-hand bearing element 7 with respect to the drawing plane in FIG. 2. As is shown in dash-dot lines in FIG. 2, coolant can flow into the coolant channel 16 a on the housing side at the location indicated by arrow 18 and arrives at the coolant-carrying plate intermediate spaces 5 via the coolant channel 15 a on the bearing element side, whereupon the coolant flows out via the coolant channel 15 b on the bearing element side and via the coolant channel 16 b on the housing side corresponding to arrow 19.

To seal the coolant channels 15, 16 relative to one another, sealing elements 20 are arranged between bearing element 7 and bearing element 8 on one side and between supports 9, 10 on the housing side which are associated with these bearing elements 7, 8.

In this case, the plate heat exchanger 3 has a medial, central recess 21 which forms a connection area for a suction pipe line 22 which is guided to the oil pump, not shown. Also, this suction pipe line 22 is sealed relative to the bearing elements 7, 8 on the heat exchanger side by sealing elements 20.

As can further be seen from the schematic view in FIG. 2, the plate assembly of the plate heat exchanger 3 is enclosed radially on the circumferential side and, therefore, annularly by a cylindrical oil screen 23 in a positive-locking manner.

As can be seen from FIG. 2, the respective oil-carrying plate intermediate spaces 6 are in direct fluidic connection with the oil 25 in the oil pan 2 by their radial openings 24 so that the oil 25 is sucked directly from the oil pan 2 via the oil screen 23 radially into the oil-carrying plate intermediate spaces 6 so that the oil subsequently flows onward in this radial direction to the central recess 21. In so doing, heat is transferred between the oil and the coolant in the coolant-carrying plate intermediate spaces 5, namely, as can be seen from the view in FIG. 2, over relatively long flow paths. Starting from the recess 21, the cooled oil is then sucked out via the suction pipe line 22. The oil flow is shown schematically by the arrows 26.

Finally, FIG. 3 shows an alternative embodiment compared with FIG. 2 in which the same structural component parts are provided with the same reference numbers. In contrast to the embodiment shown in FIG. 2, the plate heat exchanger 3 in this case is secured to the bottom wall 13 by screw connections 11. Further, there are differences with respect to the construction of the coolant channels. In this case, the coolant feed 18 takes place through a coolant channel 16 a on the housing wall side. This coolant channel 16 a extends from the side wall 12 along the bottom wall 13 through a flange plate 27, by means of which the plate heat exchanger 3 is secured to the bottom wall 13, to the plate heat exchanger 3 and, from the latter, to the coolant-carrying plate intermediate spaces 5. In this case also, sealing plugs 17 or sealing elements 20 are again provided at the corresponding locations.

On the other hand, the coolant flows out corresponding to arrow 19 via a coolant channel 16 b which extends from the housing wall of the oil pan 2 via an intermediate element 28 to a coolant channel 15 b which is formed in a bearing element 7 on the heat exchanger side. The bearing element 7 is sealed relative to the intermediate element 28, and the intermediate element 28 is sealed relative to the housing wall, by sealing elements 20.

In other respects, the construction corresponds to that of FIG. 2 with respect to the plate heat exchanger 3, coolant-carrying plate intermediate spaces 5, oil-carrying plate intermediate spaces 6, oil screen 23, and openings 24, and reference is had to the description of FIG. 2 to avoid repetition.

Of course, only the oil-carrying plate intermediate spaces 6 are fluidically connected to the oil 25 in the oil pan 2 via the openings 24. This means that the coolant side and the oil side are tightly sealed off from one another and only a desired heat transfer takes place between the two media.

The invention is not limited by the embodiments described above which are presented as examples only but can be modified in various ways within the scope of protection defined by the appended patent claims. 

1. An oil cooling device comprising: an oil pan; an oil cooler formed by a plate heat exchanger having coolant-carrying and oil-carrying plate intermediate spaces, at least some of said oil-carrying intermediate spaces having an opening into said oil pan permitting oil to flow out of said oil pan directly via said opening into said oil-carrying plate intermediate spaces.
 2. The cooling device according to claim 1, wherein said plate heat exchanger is formed by a plate assembly comprising a plurality of plates whose oil-carrying plate intermediate spaces open into said oil pan with one of a radial outer and radial inner opening with respect to said plate assembly.
 3. The cooling device according to claim 2, wherein said oil-carrying plate intermediate spaces open into said oil pan with a radial outer opening; said plate heat exchanger additionally comprising an inner oil line connection area and an oil line which is fluidically connected in an inner heat exchanger area to at least a portion of said oil-carrying plate intermediate spaces, so that hot oil flows from said oil pan radially into said oil-carrying plate intermediate spaces via said radial outer openings, and oil subsequently flows through said plate intermediate spaces while giving off heat so that cooled oil flows out via said oil line.
 4. The cooling device according to claim 3, additionally comprising a filter element for said openings through which the oil flows into said oil-carrying plate intermediate spaces.
 5. The cooling device according to claim 4, wherein said plate assembly comprises a radial outer circumferential area and said filter element annularly encloses said entire plate assembly in said radial outer circumferential area.
 6. The cooling device according to claim 3, wherein said oil line opens into said plate heat exchanger in an approximately central, medial area.
 7. The cooling device according to claim 3, wherein said oil line is formed by a suction pipe line.
 8. The cooling device according to claim 1, wherein said oil pan has a wall and said plate heat exchanger is arranged in said oil pan at a defined distance from at least a portion of said wall.
 9. The cooling device according to claim 8, additionally comprising bearing elements and wherein said plate heat exchanger is fastened, to one of supports on said housing wall side, connection elements and directly to said housing wall by means of said heat exchanger bearing elements.
 10. The cooling device according to claim 9, wherein said plate heat exchanger is supported by said heat exchanger bearing elements between two opposite oil pan housing walls.
 11. The cooling device according to claim 1, additionally comprising heat exchanger bearing elements and coolant channels integrated in said heat exchanger bearing elements and fluidically connected to at least a portion of said coolant-carrying plate intermediate spaces.
 12. The cooling device according to claim 11, wherein said oil pan comprises a housing wall and wherein said coolant channels which are fluidically connected to said coolant-carrying plate intermediate spaces are integrated at least partially in said housing wall of said oil pan.
 13. The cooling device according to claim 12, wherein said coolant channels which are integrated in said heat exchanger bearing elements are fluidically connected to at least a portion of said coolant channels which are integrated in said housing wall.
 14. The cooling device according to claim 13, wherein said coolant channels are formed by a plurality of bore holes which communicate with one another. 